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[209.132.183.28]) by mx.google.com with ESMTPS id i66si482422qtb.274.2019.06.18.09.05.50 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Jun 2019 09:05:50 -0700 (PDT) Received-SPF: pass (google.com: domain of fweimer@redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; Authentication-Results: mx.google.com; spf=pass (google.com: domain of fweimer@redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=fweimer@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 06BA17FDF9; Tue, 18 Jun 2019 16:05:39 +0000 (UTC) Received: from oldenburg2.str.redhat.com (ovpn-116-87.ams2.redhat.com [10.36.116.87]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 70CCD37DE; Tue, 18 Jun 2019 16:05:26 +0000 (UTC) From: Florian Weimer To: Yu-cheng Yu Cc: Dave Martin , Peter Zijlstra , Thomas Gleixner , x86@kernel.org, "H. Peter Anvin" , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue Subject: Re: [PATCH v7 22/27] binfmt_elf: Extract .note.gnu.property from an ELF file References: <87lfy9cq04.fsf@oldenburg2.str.redhat.com> <20190611114109.GN28398@e103592.cambridge.arm.com> <031bc55d8dcdcf4f031e6ff27c33fd52c61d33a5.camel@intel.com> <20190612093238.GQ28398@e103592.cambridge.arm.com> <87imt4jwpt.fsf@oldenburg2.str.redhat.com> <20190618091248.GB2790@e103592.cambridge.arm.com> <20190618124122.GH3419@hirez.programming.kicks-ass.net> <87ef3r9i2j.fsf@oldenburg2.str.redhat.com> <20190618125512.GJ3419@hirez.programming.kicks-ass.net> <20190618133223.GD2790@e103592.cambridge.arm.com> <87pnna7v1d.fsf@oldenburg2.str.redhat.com> <1ca57aaae8a2121731f2dcb1a137b92eed39a0d2.camel@intel.com> Date: Tue, 18 Jun 2019 18:05:24 +0200 In-Reply-To: <1ca57aaae8a2121731f2dcb1a137b92eed39a0d2.camel@intel.com> (Yu-cheng Yu's message of "Tue, 18 Jun 2019 08:53:29 -0700") Message-ID: <87blyu7ubf.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 18 Jun 2019 16:05:49 +0000 (UTC) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: * Yu-cheng Yu: >> I assumed that it would also parse the main executable and make >> adjustments based on that. > > Yes, Linux also looks at the main executable's header, but not its > NT_GNU_PROPERTY_TYPE_0 if there is a loader. > >> >> ld.so can certainly provide whatever the kernel needs. We need to tweak >> the existing loader anyway. >> >> No valid statically-linked binaries exist today, so this is not a >> consideration at this point. > > So from kernel, we look at only PT_GNU_PROPERTY? If you don't parse notes/segments in the executable for CET, then yes. We can put PT_GNU_PROPERTY into the loader. Thanks, Florian